Middleby Marshall PS200, PS570, PS360, PS555, PS220, PS224 PS310 manual

2.Checking the thermocouple with a DC millivolt meter

It is possible to check that a thermocouple is reading accurately by using a multimeter set to read DC milli- volts. At 32°F/0°C the thermocouple should read 0 mVDC. This can be checked by inserting the ther-

SECTION 3 - SERVICING COMPONENTS

mocouple into an ice bath for several minutes. At 72°F/ 22°C the reading should be 1.134mVDC.

You can use the chart below by checking the tempera- ture at the thermocouple’s junction terminals. This is called the Junction Temperature.

Figure 24 - Thermocouple millivolt readings at various operating and junction temperatures

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